A model describing the effect of enzymatic degradation on drug release from collagen minirods

Metzmacher, Iris; Radu, Florin A.; Bause, Markus; Knabner, Peter; Frieß, Wolfgang

doi:10.1016/j.ejpb.2007.02.013

Cited by 42 publications

(48 citation statements)

References 34 publications

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“…The parameters in such a model require extensive experimentation. Modern numerical techniques have been used (Göpferich and Langer, 1993;Wang et al, 2008;Yu et al, 2008;Han and Pan, 2009;Bikiaris et al, 2007;Metzmacher et al, 2007) to solve the corresponding equations for devices of both simple and complicated geometries, in the context of drug release devices. However, none of these models were able to predict the mechanical properties evolution of the device.…”

Section: Introductionmentioning

confidence: 99%

Mechanical study of PLA–PCL fibers during in vitro degradation

Vieira

Vieira²,

Ferra

et al. 2011

Journal of the Mechanical Behavior of Biomedical Materials

221

128

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Abstract:The aliphatic polyesters are widely used in biomedical applications since they are susceptible to hydrolytic and/or enzymatic chain cleavage, leading to α-hydroxyacids, generally metabolized in the human body. This is particularly useful for many biomedical applications, particularly, for temporary mechanical supports in regenerative medical devices.Ideally, the degradation should be compatible with the tissue recovering.In this work, the mechanical properties evolution during degradation are discussed based on experimental data. The decrease of tensile strength of PLA-PCL fibers follows the same trend as the decrease of molecular weight, and so it can also be modeled using a first order equation. For each degradation stage, hyper elastic models such as neo-Hookean, MooneyRivlin and second reduced order, allowed a reasonable approximation of the material behavior. Based on this knowledge, constitutive models that describe the mechanical behavior during degradation are proposed and experimentally validated. The proposed theoretical models and methods may be adapted and used in other biodegradable materials, and can be considered fundamental tools in the design of regenerative medical devices where strain energy is an important requirement, such as ligaments, cartilage, stents or others.

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Section: Introductionmentioning

confidence: 99%

Mechanical study of PLA–PCL fibers during in vitro degradation

Vieira

Vieira²,

Ferra

et al. 2011

Journal of the Mechanical Behavior of Biomedical Materials

221

128

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“…All the parameters used (Table 1) are taken from [17] and we also use the same time-dependent boundary conditions as in [17]. We observe a very good agreement between the numerical simulation and the experiments for both collagen degradation and drug release, see Fig.…”

Section: Comparison With Experimental Resultsmentioning

confidence: 48%

“…The results for the choice of the parameter value γ = 0.5 are compared with the experimental data for DEXTRAN 70 from [17]. All the parameters used (Table 1) are taken from [17] and we also use the same time-dependent boundary conditions as in [17].…”

Section: Comparison With Experimental Resultsmentioning

confidence: 99%

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Drug release from collagen matrices including an evolving microstructure

et al. 2013

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Biodegradable collagen matrices have become a promising alternative to traditional drug delivery systems. The relevant mechanisms in controlled drug release are the diffusion of water into the collagen matrix, the swelling of the matrix coming along with drug release, and enzymatic degradation of the matrix with additional simultaneous drug release. These phenomena have been extensively studied in the past experimentally, via numerical simulations as well as analytically. However, a rigorous derivation of the macroscopic model description, which includes the evolving microstructure due to the degradation process, is still lacking. Since matrix degradation leads to the release of physically entrapped active agent, a good understanding of these phenomena is very important. We present such a derivation using formal twoscale asymptotic expansion in a level set framework and complete our results with numerical simulations in comparison with experimental data.

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“…The parameters in such a model require extensive experimentation. Numerical techniques have been used (Göpferich and Langer 1993;Wang et al 2008;Yu et al 2008;Han and Pan 2009;Bikiaris et al 2007;Metzmacher et al 2007) to solve the corresponding equations for devices of both simple and complicated geometries, in the context of drug release systems. However, these models did not account for the mechanical properties degradation of these devices.…”

Section: Biodegradation and Erosionmentioning

confidence: 99%

4D Numerical Analysis of Scaffolds: A New Approach

Vieira¹,

Marques

Guedes

et al. 2014

Tissue Engineering

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A large range of biodegradable polymers are used to produce scaffolds for tissue engineering, which temporarily replace the biomechanical functions of a biologic tissue while it progressively regenerates its capacities. However, the mechanical behavior of biodegradable materials during its degradation, which is an important aspect of the scaffold design, is still an unexplored subject. For a biodegradable scaffold, performance will decrease along its degradation, ideally in accordance to the regeneration of the biologic tissue, avoiding the stress shielding effect or the premature rupture. In this chapter, a new numerical approach to predict the mechanical behavior of complex 3D scaffolds during degradation time (the 4 th dimension) is presented. The degradation of mechanical properties should ideally be compatible to the tissue regeneration. With this new approach, an iterative process of optimization is possible to achieve an ideal solution in terms of mechanical behavior and degradation time. The scaffold can therefore be prevalidated in terms of functional compatibility. An example of application of this approach is demonstrated at the end of this chapter.

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A model describing the effect of enzymatic degradation on drug release from collagen minirods

Cited by 42 publications

References 34 publications

Mechanical study of PLA–PCL fibers during in vitro degradation

Mechanical study of PLA–PCL fibers during in vitro degradation

Drug release from collagen matrices including an evolving microstructure

4D Numerical Analysis of Scaffolds: A New Approach

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